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Occupational Audiometric Testing Part 2: Interpretation and Referral Thomas W. Rimmer, ScD, CIH Fay W. Boozman College of Public Health University of Arkansas.

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Presentation on theme: "Occupational Audiometric Testing Part 2: Interpretation and Referral Thomas W. Rimmer, ScD, CIH Fay W. Boozman College of Public Health University of Arkansas."— Presentation transcript:

1 Occupational Audiometric Testing Part 2: Interpretation and Referral Thomas W. Rimmer, ScD, CIH Fay W. Boozman College of Public Health University of Arkansas for Medical Sciences This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivs 2.5 License. To view a copy of this license, visit

2 2 Interpretation of results Comparison of annual to baseline, one ear at a time Threshold Annual – Threshold Baseline = threshold shift Baseline, RE Annual, RE Threshold shift

3 3 Standard Threshold Shift (STS) 10 dB average shift at 2, 3 & 4 kHz Each ear computed separately 10 dB average shift in either ear is STS Either average shifts or subtract threshold averages AVG Baseline, RE Annual, RE Threshold shift

4 4 Other factors in STS determination Test error or short term loss Retest allowed within 30 days Age correction allowed Subtracts normal aging loss from threshold shift Age M F

5 5 STS - work related? Determination by health care professional Factors for determination Workplace noise exposure Hearing protection on the job Non-occupational factors Noisy hobbies, sports, other jobs Lack of protection Only make determination of non-work-related if no significant contribution to hearing loss due to workplace factors

6 6 STS actions Notify worker in writing within 21 days Re-train and re-fit hearing protectors Change to new baseline if STS persistent Possibly record as occupational illness or injury Refer for medical evaluation if ear infection caused/aggravated by HPD

7 7 Baseline revision STS - if present on two consecutive Improvement - 5dB average (2,3,4 kHz) on two consecutive audiograms General rules: Revise to the better (or earlier) audiogram Revise each ear separately Revise all frequencies in each ear together Subject to professional judgment

8 8 Recordability of hearing loss Meets all STS requirements and Average hearing level 25 dB at 2, 3 & 4 kHz in the same ear Recording requirements Within 7 days of test on OSHA 300 log May later be deleted if change isnt permanent

9 9 Determination of hearing impairment Average thresholds at 0.5, 1, 2, & 3 kHz Determine degree of impairment, if any 0-24 dB, normal range dB, mild hearing loss dB, moderate loss dB, moderately severe loss dB, severe loss >85 dB, profound loss

10 10 Percentage of hearing loss Average thresholds at 0.5, 1, 2, & 3 kHz Subtract 25 dB from result (normal hearing) Multiply result by 1.5% Repeat for each ear Avg.% Right Ear Left Ear

11 Binaural impairment calculation Since hearing isnt averaged by ears, consider better ear more strongly 1. Multiply loss in better ear by 5 2. Add loss in poorer ear 3. Divide total by 6 for binaural loss (4% x %) = 31% 31% ÷ 6 = 5%

12 12 Problem audiograms - medical Large shift in short period Large shift in one ear only Ear pain, dizziness, onset of tinnitus

13 13 Problem audiograms - measurement Cross hearing situation Uncooperative or difficult subject Hearing impaired subject

14 14 Referral to specialist Medical problems Employer payment? Measurement problems Interpretation problems Standard threshold shift - work related? Recordable on OSHA log - work related? Baseline revision

15 15 Recordkeeping What audiometric records must be kept Name of employee & examiner, date of test Threshold results Calibration date of audiometer Noise exposure assessment of employee How long to keep OSHA: duration of employment Others: extended period Other records to keep Background noise, hearing history, training of examiner, daily calibration log

16 16 Summary Interpretation STS calculation - 10 dB 2,3,4 kHz STS actions and recordability Impairment to 3000 Hz, >25 dB Referral of problem audiograms Medical Measurement Recordkeeping

17 17 End of Part 2


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